>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3568427. --> Reported by: [mxr576](https://www.drupal.org/user/315522) Related to !179 >>> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>Mercury theme library definitions currently include a <code>VERSION</code> string in <code>*.libraries.yml</code>. In Drupal core, the <code>VERSION</code> constant refers to the Drupal core version. Contributed modules and themes should not rely on that value for asset versioning, because it can lead to stale assets being served after CSS/JS changes.</p> <p>This is especially risky behind CDNs and other intermediate caches: if the theme updates an asset file but the library version does not change, cache invalidation may not happen as expected, and users can receive outdated CSS/JS.</p> <h4 id="summary-steps-reproduce">Steps to reproduce</h4> <h3 id="summary-proposed-resolution">Proposed resolution</h3> <h3 id="summary-remaining-tasks">Remaining tasks</h3> <h3 id="summary-ui-changes">User interface changes</h3> <h3 id="summary-api-changes">API changes</h3> <h3 id="summary-data-model-changes">Data model changes</h3>